Friction brake



Oct. 4, 1932. r. F. BRACKETT v FRICTION BRAKE Filed Feb. 4, 1929 My 1 5 5%; O

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1 In mam HUGE w 821? W 4 Edg Patented O t. 4, 1932 UNITED sures manor 1*. BRACKETT, or NEW YORK, N. Y; nssrenoa '10 American BRAKE MATERIALS 1 conronerron, or NEW'YORK; n. Y., A coaroaa'non ornnw YORK rarcrron Application ma rebru i-y '4, 1929. Serial in. 387,201.

- This invention relates to friction brakesand more particularly to friction blocks having a composition body mounted on a metalback and adapted for use on brake bands,

shoes or heads, or other supports in friction brake assemblies of this kind.

The primary object'of the invention, is to provide a secure anchorage between the bodyand the back of the block to prevent the body from being sheared or otherwise separated from the back under the conditions of use.

And a further object of the invention is to provide the metal back with openings to receive the body material and having the edges of the openings formed in a novel manner a to (permit molding of the body on the back in said openings and to produce a button anchorage between the body and the back. In the accompanying drawing I have shown a selected embodiment of the invention and. referring thereto Fig.1 is a plan view of the outer side of a j metal back embodying the invention.

Fig. 2 is a sectional view on-the line 2 -2 of Fig; 1. a

Fig. 3is a plan view of the back of. a blockembodying the invention.

Fig. 4 is a-sectional view on the line 4-4 of Fig. 3. l

Referring to the drawing the block comprises a body 5 preferablymadeof a suitablecomposition which will 've desired braking effect and also possess 'ong wearing quality. The body is mounted on ametal back 6 which is provided with openings 7to receive the bod materialfor anchoring the body to the bee The'block is made arcuate to fit brake bands, shoes or heads but it may be made flat and in any particular shape for friction engagement with a part to braked. I prefer to make the openings 7 rectangular in form with opposite edges. thereof transverse to the len h'of the-back. .The openings "are formed ystampling and at the same time the cross bars 8 w 'ch form the openings. are shaped in the form of channels substantially arcuate in cross. section to proyide inturned flanges 9 surrounding the openings and inclining-inwardly at an angle of about tendegre'es. I

In practice the block may be made by'plac- ,m orrica ing a stamped back in a-mold' with theflanges 9 uppermost, depositing the required 'quantity of composition on the back, and then applying pressure upon the composition mass to mold it into ablock with portions 10 lo{ at their inner ends and, consequently that portion of the body seated in an opening is larger at the. outer end than it is at the inner end of the opening. This construction provides anelfective' anchorage of the body to v are larger in area at their outer ends than the metalback and it enables the anchorage to a v be eliiciently and uniformly producedlin: all

the openings ofj'the back and regularly insall backs during themold" g operation. I have found that by'inclining the flange forming the side walls of the opening 10 slightly inwardl 1 it will not'p'reventthe body material from ing pressed into the opening to com pletely fill the opening so that a solid integral button is formed in each opening completely filling the opening and anchoring the body to the back. The channel cross bars are substantially arcuate or U-shaped in'cross.section and this increases the area of the openings without correspondingly decreasing the stren h of the cross bars.

In fact bending the cross bars in or about the manner shown anddescribed increases their strength while reducing their cross section so that the back as shown in Fig. 1 is stronger with the areaate cross bars than it would be if the cross bars were flat and at the same time the openings 7 are much larger with the arcuate cross bars than they would be with the cross bars fiat and hence there is a greater area of body material employed inthe" anchoring of the body to the back than wouldbe the case if the cross bars were flat, whereby'the body is more securely anchored to ,the back. I have shown the invention embodied in a block as a comlete unit with ends 11 of the back-proLecting beyond the bodyrfor fastennig' the bloc to its support; but the inventionmaybe embodied my ing arranged end to end and connected together in a strip for use singly or in such combinations as may be desired.

The invention provides asimple but effi- I cient means whereby the composition body of a brake block may be anchored to its metal back in a strong, solid and efiicient manner to prevent the body from being torn or pulled away from the back With a shearing action under the strains of service. I prefer to make the openings substantially rectangular in shape because they can bedisposed in parallel rows extending lengthwise and transversely of the back so that opposite transverse side walls of the openings afford efiicient resistance to the strains of service. I

Rectangular openings are superior to equally spaced circular openings because the thrust resistance extends evenly throughout the entire diameter of each opening whereas with circular openings the thrust resistance is concentrated at the crown of the opening. The edges between the crown and the sides of the circular opening present shearing angles which tend to shear the composition body and lessen the resistance of the separation from the back under braking pressure. The cross bars form intersecting channels into which the body composition is pressed and'this also assists in resistance to thrust. a v 7 I have described the invention in a form which I consider desirable for the purposes intended but I'reserve the right to make any changes therein that fall within the scope of the followingclaims.

I claim:

1. A friction block comprising a composition body and a metal back therefor, said back having a plurality of channel cross bars forming substantially rectangular openings filled with bodymateriahlsaid cross bars he'- in; substantially arcnate in cross vsection.

bars.

2. A friction block having a plurality of transversely and longitudinally extending cross bars forming substantially rectangular o y enings therebetween, the cross bars being ent substantially-arcuate to form inwardly inclined flanges about each opening thereby strengthening the cross bars and providing openings smaller in area at their inner ends than at their outer ends.

' 3. A sheet metal back for a friction block having a plurality of spaced openings therein arranged in regular alignment, the parts of the back between the openings being bent substantially jarcuate in cross section and .forming intersecting channel-shaped cross TRACY F. BRACKETT.

body to sheet metal back for a composition 

